The Accuracy of Continuous Glucose Monitoring Systems in Critically Ill Patients

A trained research member placed the AiDEX® Dynamic Continuous Glucose Monitoring System (Microtech Medical Devices (Hangzhou) Co., Ltd.) on the patient's abdomen, about 3-10 cm to the left or right of the navel, or on the back of the upper arm, according to the instructions. The sensor began to collect data 1-4 hours after successful activation, recording blood glucose values every 5 minutes for 7 consecutive days. For patients who stayed in the ICU for less than 7 days, the continuous glucose monitoring (CGM) was terminated on the day of ICU discharge, and the CGM device was removed.

Patients monitored their blood glucose using fingerstick point-of-care (POC) measurements every 1-6 hours as needed and had routine arterial blood gas analysis 4-6 times a day. After 24 hours of patient wear, the arterial blood gas glucose (aBG) was used to calibrate the CGMS device at least twice a day. Nurses recorded CGMS data paired with POC values and aBG values in a 1:1 format.

This study is a single-center, prospective, observational study conducted in the Intensive Care Unit (ICU) of Nanfang Hospital, Southern Medical University, from May 2024 to August 2024. Patients with elevated blood glucose levels (BG>180 mg/dL) undergoing intravenous insulin therapy were included. Simultaneous blood glucose monitoring was performed using fingerstick blood samples and arterial blood gas analysis, along with the installation of CGMS for concurrent monitoring. CGMS data (CGM values) were recorded in a 1:1 paired format with fingerstick point-of-care (POC) values and arterial blood gas (aBG) values. The correlation of paired blood glucose data was examined using Pearson's correlation coefficient. The accuracy of CGMS was assessed using metrics such as Mean Absolute Relative Difference (MARD), ISO 15197-2013, CLSI POCT12-A3, and Clarke Error Grid Analysis, analyzed with R v.4.4.1 software.

Patients who met the inclusion and exclusion criteria were enrolled in the study after obtaining informed consent from the patient or their legal representative. A trained research member placed the AiDEX® Dynamic Continuous Glucose Monitoring System (Microtech Medical Devices (Hangzhou) Co., Ltd.) on the patient's abdomen, about 3-10 cm to the left or right of the navel, or on the back of the upper arm, according to the instructions. The sensor began to collect data 1-4 hours after successful activation, recording blood glucose values every 5 minutes for 7 consecutive days. For patients who stayed in the ICU for less than 7 days, the continuous glucose monitoring (CGM) was terminated on the day of ICU discharge, and the CGM device was removed.